Continuous rod making machines

ABSTRACT

A cigarette filter rod making machine has a diameter control comprising a platen which moves up and down in response to signals from a diameter-sensing device. The platen is positioned by a servomotor which preferably controls the platen via a gear train and a differential screw drive.

United States Patent Rakowicz Feb. 29, 1972 [54] CONTINUOUS ROD MAKING [56] References Cited MACHINES UNITED STATES PATENTS [72] Invent: Jan Rakmvicz England 3,380,351 4/1968 Cox et al .;.....93/1 0 [73] Assignee: Molins Machine Company Limited 2,952,262 9/1960 Pocock et al ..l3l/2l B [22] Filed: 1970 Primary ExaminerBemard Stickney [21] Appl.No.: 26,316 Attorney-Markva& Smith [57] ABSTRACT [30] Foreign Application Priority Data I A cigarette filter rod making machine has a diameter control Apr. 10, 1969 Great Britain ..l8,393/69 comprising a platen which moves up and down i response to signals from a diameter-sensing device. The platen is posi- [52] U.S. Cl. ..93/] C, l3l/21 B tioned by a servomotor which preferably eomrols the platen [51] Int. Cl ..B31d via a gear train d a differential Screw drive [58] Field ofSeai-ch ..93/l C; 131/21 B 6 Claims, 4 Drawing Figures PAIENTEDFEB29 m2 SHEET 1 OF 2 JAN ANTONI RAKOWICZ I nuentor 041/ azhefi dxl 777d/t 4W55/222% Allorney PATENTEDFEB29 I972 SHEET 2 [IF 2 L r l IL L J Fr JAN ANTON! RAKOWICZ Inventor 411 imeifa/a max/5w A Home y CONTINUOUS ROI) MAKING MACHINES This invention relates to continuous rod making machines and particularly to cigarette filter rod making machines.

According to the present invention a continuous rod making machine includes a rod diameter control comprising a platen which is mounted above a gamiture bed and is movable vertically by an actuating mechanism to vary the diameter of a passage formed between the platen and the gamiture bed, the actuating mechanism comprising a servomotor which drives a threaded member through gearing, the threaded member being connected to the platen to convert the rotational movement of the gearing into the linear movement of the platen.

How the invention will be carried out will now be described with reference to the accompanying drawings in which:

FIG. 1 is a side elevational, part-sectional view of a cigarette filter rod making machine incorporating the present inven tion;

FIG. 2 is a section taken on the line A-A of FIG. 1;

FIG. 3 is a section taken on the line 8-3 of FIG. 2; and

FIG. 4 is a block diagram showing the control system for the diameter control. The machine shown includes a gamiture bed 1 over which a continuous gamiture tape 2 passes, a foldin'g arrangement 3 being positioned above the gamiture bed 1 to fold a continuous wrapper tape 9 around the filter material.

A tongue assembly 4 is positioned upstream of the folding arrangement 3 to compress the filter material to form the rod. The details concerning the construction of the tongue assembly 4 are disclosed in copending U.S. application Ser. No.26,3l5, filed Apr. 7, 1070, in the name of Horace Alexander Stone.

The gamiture tape 2 passes around the rollers 6, 7 and 8, the roller 6 being mounted on a swinging arm so that the portion 2a of the gamiture tape 2 can be moved a limited amount in a plane substantially normal to the plane of the drawing to centralize the gamiture tape on the gamiture bed 1.

The wrapper 9 passes around the roller 10 from a spool (not shown) via an adhesive-applying station (not shown) by which adhesive is applied along one edge of the wrapper. The adhesive is heat-sensitive polyvinyl acetate (p.v.a.).

The folding arrangement comprises a first folder 11 which folds over a first edge of the wrapper 9, and downstream of the first folder 1] is a second folder 12 which folds down the second glued edge of the wrapper 9. A diameter control 53 is automatically adjustable in a vertical direction by a servomotor 13 (see FIG. 3) in response to signals indicative of rod diameter from a sensor 14 to correct trends in variations of the rod diameter. A heater 15 is positioned downstream of the diameter control 53 to heat the p.v.a. adhesive on the wrapper.

The way in which the diameter control 53 is automatically adjusted to correct trends in variations of the rod diameter will now be described in detail.

A platen 17 (FIG. 2) is mounted on an arm 16 which is hinged at 18 to a main frame of the machine. The lower surface of the platen 17 has a substantially semicircular groove 19 formed in it which together with the groove in the gamiture bed 1, forms a passage of substantially circular cross section through which the rod 20 passes. The bottom of the groove 19 (i.e., the central region) may have a flat portion formed on it (not shown) to facilitate the folding over and glueing of the second edge of the wrapper.

During use, upward movement of the arm 16 is limited by a clamp 21 reacting against a head 22 of a spindle 23 which has a smaller-diameter upper section which passes through a slot 24 in the arm 16. The head 22 is screwed on to the upper end of the spindle 23. A spring 24 surrounding the smaller-diameter upper section of the spindle urges the clamp 21 upwards against the head 22. The rod 20 will be formed with a diameter equal to that allowed by the maximum upward movement of the platen 17. Hence vertical movement of the head 22 will vary the diameter of the rod.

In order to raise the arm 16, the clamp 21 is rotated through 90 to a position in which the clamp can pass through the slot in the ann l6.

Vertical movement of the stud 23, and hence the head 22, can be effected by means of the servomotor 13 through gearing generally indicated by 25, and a threaded arrangement, generally indicated by 26.

The servomotor 13 has an output shaft 27 which drives a first gear 28. The first gear 28 is in mesh with a second gear 29 formed on a sleeve 30. The sleeve 30 has two bores 31 and 32 which are of different diameters and formed with threads of different pitches. A threaded stud 33, which is integral with a part 34 of the servomotor casing, engages in the threaded bore 31 of the sleeve 30. The lower end of the stud 23 is threaded at 35 and engages in the threaded bore 32 of the sleeve 30. The stud 23 is carried in a bearing 36 mounted in the servomotor casing.

Energization of the servomotor 13 will cause rotation of the sleeve 30 through the gearing 28 and 29. The rotation of the sleeve 30 will cause it to move either up or down the fixed threaded stud 31, depending upon the direction of rotation of the output shaft 27 of the servomotor. This vertical movement of the sleeve 30 will be transmitted to the stud 23 through its threaded end 35, but the amount of vertical movement of the stud 23 will be different from the vertical movement of the sleeve 30 owing to the fact that the pitches of the threads on 31 and 35 are different. The thread 35 is finer than the thread 31. Therefore the stud 23 moves a smaller amount than sleeve 30 for each increment of rotation of the output shaft 27 of the servomotor. The gears 28 and 29 are also selected to give a gearing reduction.

As stated previously, the servomotor 13 is controlled by a sensor 14 and the arrangement by which this is done is shown schematically in FIG. 4.

The sensor 14 senses the diameter of the rod by passing air into a chamber through which the rod passes, the rate of flow of air through the chamber decreasing with increasing rod diameter and thus giving rise to an increase in back pressure in the air supply. Air is supplied from a pump 51 through a regulator 52 to a pressure transducer 38.

The pressure transducer 38 comprises a first chamber 39 having an inlet 41 and an outlet 40 and with a first diaphragm 42 forming a wall of the chamber 39. The transducer 38 has a second chamber 43 with an inlet 45 and outlet 44 and with a second flexible diaphragm 46 forming a wall of the chamber 43. A metal core 47 interconnects the two flexible diaphragms 42 and 46 and passes through a coil 48. Movement of the core 46 within the coil 48 generates an electrical signal which is fed to an amplifier 49 (including a meter) which in turn supplies a signal to the servomotor 13.

A restrictor 50 is fitted to the outlet 44 of the chamber 43 to produce a predetermined reference back pressure in the chamber 43.

When the diameter of the rod, as indicated by the sensor 40, corresponds with that required, the back pressures in the two chambers 39 and 43 are equal and there is therefore no movement of the core 47 within the coil 48. However, when the diameter of the rod, as indicated by the sensor 40, is either too large or too small there will be a consequent increase or reduction respectively in the back pressure in the chamber 39 and consequent movement of the core 47 within the coil 48. A signal thus generated and applied to the servomotor 13 will cause linear movement of the stud 23 and consequent adjustment of the platen 17 to vary the diameter of the rod 20.

One example of a suitable diameter sensor is described in U.S. Pat. No. 2,952,262 to Pocock et al.

Arrangements other than that shown in FIG. 4 for obtaining the control signal for the servomotor may be employed.

What I claim as my invention and desire to secure by Letters Patent is:

1. A continuous rod making machine including a rod diameter control comprising:

a. a gamiture bed for supporting a continuous rod,

b. a movably mounted platen spaced from said gamiture bed,

c. said gamiture bed and platen together defining a passage for a continuous rod therebetween, and

d. means for moving said platen towards and away from said gamiture bed to vary the diameter of said passage,

e. said moving means including reversible drive means and a differential screw arrangement actuated by said drive means, I

f. said differential screw arrangement including a stationarily mounted first threaded member, a second threaded member connected to said movable platen, said threaded members being in alignment with each other and the pitch of the first threaded member being different from the pitch of the second threaded member, and a third rotatable member extending between said first and second threaded members and having threads complimentary to those of both said first and second threaded members,

g. whereby actuation of said reversible drive means rotates said third rotatable member to move said second threaded member with respect to said first threaded member and said platen with respect to said gamiture be to control the diameter of the rod.

2. A continuous rod making machine according to claim 1 wherein said first and second threaded members are first and second externally threaded rods respectively and said third threaded member is an internally threaded sleeve.

3. A continuous rod making machine according to claim 2 wherein said internally threaded sleeve is formed as a gear operatively connected to said reversible drive means.

4. A continuous rod making machine according to claim 2 further comprising a pivotably mounted means for supporting said movable platen and releasable clamping means for securing said second rod to said platen.

5. A continuous rod making machine according to claim 1 further comprising means for sensing the diameter of said continuous rod and generating a signal indicative of the rod diameter to actuate said reversible drive means to control the rod diameter.

6. A continuous rod making machine according to claim 5 wherein said sensing means comprises diaphragm means responsive to fluid pressure variations resulting from fluctuations in rod diameter and, in combination, a metal coil and a metal core movable with respect to each other by said diaphragm means for generating an electrical signal for controlling said reversible drive means. 

1. A continuous rod making machine including a rod diameter control comprising: a. a garniture bed for supporting a continuous rod, b. a movably mounted platen spaced from said garniture bed, c. said garniture bed and platen together defining a passage for a continuous rod therebetween, and d. means for moving said platen towards and away from said garniture bed to vary the diameter of said passage, e. said moving means including reversible drive means and a differential screw arrangement actuated by said drive means, f. said differential screw arrangement including a stationarily mounted first threaded member, a second threaded member connected to said movable platen, said threaded members being in alignment with each other and the pitch of the first threaded member being different from the pitch of the second threaded member, and a third rotatable member extending between said first and second threaded members and having threads complimentary to those of both said first and second threaded members, g. whereby actuation of said reversible drive means rotates said third rotatable member to move said second threaded member with respect to said first threaded member and said platen with respect to said garniture bed to control the diameter of the rod.
 2. A continuous rod making machine according to claim 1 wherein said first and second threaded members are first and second externally threaded rods respectively and said third threaded member is an internally threaded sleeve.
 3. A continuous rod making machine according to claim 2 wherein said internally threaded sleeve is formed as a gear operatively connected to said reversible drive means.
 4. A continuous rod making machine according to claim 2 further comprising a pivotably mounted means for supporting said movable platen and releasable clamping means for securing said second rod to said platen.
 5. A continuous rod making machine according to claim 1 further comprising means for sensing the diameter of said continuous rod and generating a signal indicative of the rod diameter to actuate said reversible drive means to control the rod diameter.
 6. A continuous rod making machine according to claim 5 wherein said sensing means comprises diaphragm means responsive to fluid pressure variations resulting from fluctuations in rod diameter and, in combination, a metal coil and a metal core movable with respect to each other by said diaphragm means for generating an electrical signal for controlling said reversible drive means. 